Effects of Excessive Nutrient Supply and Short Day Treatment on Autumn Frost Hardiness and Time of Bud Break in Picea abies Seedlings

2002 ◽  
Vol 17 (4) ◽  
pp. 295-303 ◽  
Author(s):  
Inger Sundheim Fløistad
2000 ◽  
Vol 30 (7) ◽  
pp. 1096-1105 ◽  
Author(s):  
C DB Hawkins ◽  
K B Shewan

Fifteen seed lots, five each from natural-stand, seed-orchard, and full-sib collections, of interior spruce (Picea glauca (Moench) Voss, Picea engelmannii Parry ex Engelm., and their naturally occurring hybrids) were sown in February 1993. One half of each seed lot received an ambient photoperiod (control) treatment, while the other half got a blackout (short-day) treatment. All seedlings were grown under ambient photoperiod except during the 17 days of blackout. Frost hardiness assessments were done between July and May. Blackout treatment was effective in regulating height and promoting frost hardiness in all seed lots, particularly vigorous ones. Seed lots originating from high latitude or elevation were more frost hardy both at fall lift and spring planting. Full-sib seed lots from similar latitude displayed no elevational frost-hardiness trend. Blackout treatment promoted seedling dormancy (estimated with days to bud break) at lift, but it had little or no effect on dormancy at planting. Seedling dormancy and frost hardiness were acquired and lost differently, suggesting that they are independent physiological processes. Blackout treatment significantly reduced new roots at planting in all lots. This could retard early field performance and negate the apparent utility of blackout treatment.


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Inger Sundheim Fløistad ◽  
A Granhus

Short-day (SD) treatment is used by forest nurseries to induce growth cessation in Picea abies seedlings. SD treatment may however increase the risk of reflushing in autumn and earlier bud break the following spring. We tested how different starting dates and durations of SD treatment influenced on morphological and phenological traits. Regardless of timing and duration of the SD treatment, height growth was reduced compared to the untreated controls. Seedlings given split SD (7+7 days interrupted with two weeks in long days) had less height growth than all other treatments. Root collar diameter growth was significantly less in control seedlings than in seedlings exposed to early (7 or 14 days) or split (7+7 days) SD treatment. There were also differences in the frequency of reflushing and bud break timing among the SD treated seedlings, dependent on duration and starting date. If the SD treatment started early, a continuous 14-day SD treatment was not sufficient to avoid high frequencies of reflushing. However, by splitting the SD treatment into two periods of 7+7 days these negative effects were largely avoided, although spring bud break occurred earlier than in the controls.


1993 ◽  
Vol 23 (2) ◽  
pp. 219-228 ◽  
Author(s):  
Francine J. Bigras ◽  
André L. D'Aoust

To determine frost tolerance of shoots and roots and the phenology of apical buds under different photoperiods during hardening and dehardening, 16-week-old white spruce seedlings (Piceaglauca (Moench) Voss) were hardened in growth chambers under 8-, 10-, 12-, and 14-h photoperiods for 14 d at 15:10 °C, followed by 14 d at each of the day:night temperatures of 12:8 °C, 10:5 °C, 5:2 °C under 13-h photoperiod, and finally, stored for 35 d at 0:0 °C in darkness. Afterwards, deacclimation conditions consisted of 14 d at 10:5 °C and 17 d at 15:10 °C with 15-h photoperiod. Frost tolerance was assessed at intervals, and phenology of apical buds was monitored by visual examination. The root dry mass remaining after removal of dead tissue was weighed 30 d after the freezing test to estimate frost damage to the root system. Results showed that hardening of shoots was influenced by photoperiod, whereas hardening of roots responded only to temperature. Frost tolerance of shoots was enhanced and bud formation accelerated under 8-h photoperiod. After 56 d of acclimation, frost tolerance of shoots reached −30, −17, −17, and −12 °C under photoperiods of 8, 10, 12, and 14 h, respectively. Bud break occurred earlier, in a similar fashion for plants treated with 8- and 10-h photoperiods. The root dry mass remaining after removal of dead tissue provided a reliable estimate of frost damage to root systems. Finally, we propose that short-day treatment accelerates and long-day treatment delays the dormancy development, thus causing all developmental processes to be affected. Consequently, hardiness development can also be accelerated by short-day treatment or delayed by long-day treatment, resulting in faster rates of hardening, dehardening, and bud break for seedlings of the short-day treatment, whereas long-day treatment delays those processes. These results complement the analysis of dehardening and bud break in the degree growth stage model described by L.H. Fuchigami and coworkers.


2010 ◽  
Vol 40 (5) ◽  
pp. 968-976 ◽  
Author(s):  
Inger Sundheim Fløistad ◽  
Aksel Granhus

Spring frost may result in detrimental damage in newly planted Picea abies (L.) Karst. seedlings if their growth rhythm is not sufficiently adapted to the climatic conditions on the forest site. The aims of this study were to evaluate how bud break and spring frost hardiness were influenced by short-day (SD) treatments with different timing and different temperature regimes during bud formation. Following winter storage, frost hardiness was tested after 1, 3 and 5 weeks in forcing conditions. The SD treatment advanced bud break compared with the control seedlings. In comparison, the effects of timing and the different temperatures on bud break were small. The SD treatment improved frost hardiness in first-year needles during dehardening. The early SD treatment resulted in improved frost hardiness in first-year needles and greater root collar diameter compared with later SD treatment. To avoid a second bud flush, it is important that a critical night length is attained when the SD treatment terminates. Low temperatures following the SD treatment resulted in increased hardiness of the needles and decreased hardiness of the stems. The contrasting effect of temperature in different plant tissues demonstrates the importance of examining different tissues following freezing tests.


1992 ◽  
Vol 22 (3) ◽  
pp. 388-396 ◽  
Author(s):  
Francine J. Blgras ◽  
André L. D'aoust

Containerized black spruce (Piceamariana (Mill.) B.S.P.) and white spruce (Piceaglauca (Moench) Voss) seedlings that were 120 days old were acclimated under short-day (8-h photoperiod) and long-day (16-h photoperiod) conditions at 10 °C for 12 h and 5 °C for 12 h for 28 days. Afterwards, they were exposed to 3 °C (8-h photoperiod) for 21 days and to 0 °C (without light) for 28 days. Finally, seedlings were dehardened at 10 °C (14-h photoperiod) for 21 days. Hardening of needles, excised stem parts, and whole seedlings was increased by short-day treatment, whereas roots hardened only in response to lowering of temperature. Whole seedlings and needles exposed to the short-day treatment dehardened earlier, whereas roots dehardened only in response to temperature changes. Bud formation was not influenced by photoperiod treatment, but seedlings exposed to the short-day treatment had an earlier bud break. No significant difference was observed between photoperiod treatments for water, sugar, and mineral content of shoots and roots prior to or during dehardening.


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